What to do from the beginning of battle till the end?

If you are new at soulkeep and all you have to do is put towers in the map to start the game with and with a gate that has only limited hearts then you are wrong as there are somethings to be done before the end of the battle and you have to start with it wisely.

You have to check fiends types that would start the game and as you do not know you can do it from the main menu just before press battle start and in this case you could expect fiends and then put your towers.

Other plan is to start the game and lose and then try again after you knew fiends that came to you and then put your towers that are suitable for fiends.

You can also check the arrows to see the direction of fiends that would come to your gate and this with a levels that has more than a way that fiends are coming with and for levels with one way just follow the first step and start to put towers with low mana from the beginning till the gate.