I was able to run the default AR template after much trouble with sdk,ndk versions, and I can place my own mesh in BP_placeable class and view it. Now I want to add an option on start screen off the app which will show preview of a few models , and after tapping on the desired model the app will continue as usual, here[image below] I thing I want to place separate meshes in different BP_class and input the value which i will get from user tap in the spawn actor class input, but I have no Idea how do I go about it as an absolute beginner , can someone give some guidance?
Make the class a variable
I gather this is in the pawn, so I don’t know where in particular you are going to set that variable 
I tried using a combobox and set the value in a actor variable , image 1
I just made visible by adding in startMenu blueprint by adding a branch , image 2
I tried getting the modelAR variable from BP_selectModel blueprint where I created the combobox and put the value in spawn actor in BP_ARPawn, the app is running but nothing shows up after model placement, or by selecting different options in the combobox, I am editing on the demo handheld AR project which shows up on game when you start unreal.
I am absolutely new to this, I haven’t done anything other that directly following the tutorials.
How did you set Target0?
Right clicked to promote to variable.
this was when I added my mesh in BP_Placeable blueprint instead of the default one.
this is the result now.
So you get ’ accessed none’ errors when you stop running?
*This blueprint (self) is not a BP_selectModel_C, therefore ’ Target ’ must have a connection.
*Variable node Get modelAR uses an invalid target. It may depend on a node that is not connected to the execution chain, and got purged.
these 2 errors