I had the last free stuff"playbuildsystem".When i played it and had some buildings alike,i just want to save these things to the level.how can i work it out???

As set forth,i installed the “playbuildsystem” and maked a project.Then i played the demo,i built somethings and felt good.So i want those things to be saved for next use,but i found that’s not so simple for me.The question comes:Is there some good method to store the level’s immediate state(In other words,modifications made to the level)when in PIE to the level files or a copy of it(ie,When you play a releasing one,you do some changes to the level or the game,then"F5"(or some one)pressed and you get things saved.Lately you can start from that point).However the mechanism is’t so alike.
There are some save systems or tools for releasing game to save game state or status.None found meet what i specified ahead.
How can i make it out?Some blueprint commands or c++ source codes?