The first thing you should know about onslaughts is that it is a normal attack with more participants then only one (you can start it with one participant too, but that is not the original meaning of the word). You see onslaughts that are active in the onslaught tab in the homescreen of your clan. If you have started it, you can also find it in your warbloc. You can see who is ready in the onslaught by clicking on your mead hall, and then the tab ''ready for onslaught''. It is important to note that each participant in the onslaught holds their own stats, so the one who is hosting the onslaught does not give any bonuses to other participants! 

ONSLAUGHT STRATEGIES

Since the update in June 2017 you can start the onslaught whenever you want. This is a huge advantage in comparison to earlier when you had to wait for at least 5 minutes before you could start the onslaught. If you have enough troops in the onslaught you can start an 8-hour onslaught, and send it already after 1 minute for example. You need to fill 25% of what the onslaught size caps at though. So, if you for example have a 20m onslaught size it needs to be filled with 5m troops before you can send it. 

ACTIVE ENEMY-STRATEGY

In this strategy you try to follow an active enemy who is relocating around attacking several players. The target shields up after each attack and generally does things like a typical player does. If you are fast enough you will be able to start an onslaught against the target while his shield is down. When the onslaught has started you can fill it up with clanmates, and wait for the target to unshield again (it needs to be on the same location!). Since you already have the onslaught ready, the only thing you have to do is start it and speed up the march and hope that it reaches the target before it takes its shield up (or he has relocates). If he has relocated, but later on relocates back on the same coordinates you can still send the onslaught though. 

OFFLINE ENEMY-STRATEGY

This is the easiest one, you just start an onslaught against someone who accidentally became unshielded while he was offline, and attack. It is best to maybe onslaught from a distance in case clanmates of the one you are onslaughting see the onslaught and start reinforcing (or if the target logs on and sees a hive of enemies outside his town). I usually park at least 20-30 km away from the enemy so that he doesnt see me the moment he goes to his map (or above 60km if i want to avoid being seen in his watchtower). 

TRAP-STRATEGY

In this strategy you start an onslaught against a random town (for example a clanless lvl 16 town, does not really matter), and then you ask your clanmates to fill up your onslaught. Make sure to start an 8-hour onslaught so that you have plenty of time to fill it up. When the onslaught is filled up with clanmates, you just unshield and wait for someone to attack you. I like to say that it is best to have a small army inside your town (for example 50k t1) so that you can attack unshielded towns or tiles to cause attention. It is best to use a low-influenced player for this kind of trap, because then the enemy is less likely to start a huge onslaught against it. If for example a level 26 town has its mead hall and war bloc maxed you can have it reinforced with maximum around 11m troops if you have all knowledge maxed for a level 26 town too, which is a pretty powerful tool if used correctly. You can also switch equipment while having the onslaught active, but to be able to do this you need to have optimally have a double hero active (or you can send purely your shaman into the onslaught). If you have a strong shaman and alot of your own troops are in the town it is better to have a double hero active. Because if you send your shaman into the onslaught it will not help your troops in defending your town. To use your double hero you do the following:

1. Send your first hero out of your town

2. Start the onslaught with second hero

3. Recall your first hero

4. Now you can change equipment and hero set while having the onslaught active

Also, it is best to start the onslaught by sending 1 t6 or t5, because if you send for example 1 t1, the onslaught will automatically get cancelled if the enemy attacks your town (since t1's gets killed first)

HAVE FUN OUT THERE! HOPE THIS TUTORIAL WAS HELPFUL! :)

Game-id: 4699027