Press "New" (new mapping) and choose android 7.1 (first time memu download android 7.1 files from internet)
Go to folder \memu\image\71\
delete MEmu71-2019030700003FFF-disk1.vmdk and MEmu71-2019030700003FFF-disk2.vmdk
copy two *.vdmk files here from microGfor6.1.1(7.1).zip
Open Multi-Memu and if you see any instance here, delete.
Press "New" (new mapping) and choose android 7.1. Now memu make 7.1 instance with files from microGfor6.1.1(7.1).zip
If you have problem with built-in browser (account linking) install chrome from appstore.
PS or just use 5.1 guide.