Horus Heresy: Drop Assault is a mobile game where players build up a base and use it to recruit and upgrade units. These units are then used to perform assaults on other players' bases (and NPC bases).
Players can also join a chapter, which is a community of players who play together and can share in each others rewards.
The game also includes other modes, such as skirmish (PvP battle arena), and seige mode, where chapters work together to destroy bases, giving the chapter extra resources if they succeed.
The game can be played casually but is also highly competitive. Every successful assault grants the player resources but also glory. And winning skirmish battles grants the player honour. Getting a lot of glory/honour grants further rewards as you compete in weekly tournaments. Glory/honour earned by a player contributes to their chapter's glory/honour, and there are monthly tournaments where each player gets extra resources based on the success of their chapter.
For this reason, competitive players should join a high-performing chapter to reap even more rewards. Which can in turn be used to improve their army and heroes.
This guide is intended to help competitive players maximize their ability to succeed in these tournaments. But even for casual players, this guide can help make the game less frustrating when it seems too difficult.
Note: While it is possible to spend real money to improve your army, it is not necessary, and the game is designed to still be competitive without spending any real money.