The entity report? You just use that to manage your entities. You can select an entity's properties from the entity report, or you can select the entity, right click on it in a 2D viewport, and click properties, which is what I do. I guess the entity report would help if you can't physically find the entity you're looking for, but they both get you to the same properties window.
Anyway, yeah, just change the entity's class to info_player_start (or whatever starting point entity you need), and the entity will become what you choose. You'll only notice one variable for a starting point entity, which is the pitch yaw and roll. Change those if you want to set the direction the player will be facing when he spawns there (yaw), otherwise just leave it. Close the window and that's set as a spawn location. Just make sure it isn't too close to any brushes, or the player will get "stuck" in a brush when they spawn there.