Well the setting "make first section free" is added on user demand in theme after we completed app code . So it is not supported in wplms app as of now.
But we will be supporting it in future .
Also free units in app is also not supported . this is also pending.
Well you need to tap on the user icon to open the login page .
refer : http://prntscr.com/iouh3c
On website you can enable " Open Login popup for non logged in users when they click on take this course button " . to open the login popup when user clicks on course button .