Having issue with my submenu for a website


I dont know why but I am facing an irrelevant issue, First of all I am new to figma and
have decent knowledge about it.
i was making a submenu in a website,

Now im stuck at this , i want to create a submenu of class 6 which will include subjects.
But i am not able to do it.
Tried adding a frame and using open overlay interaction but frame is not visible in such case.
plz can anyone help me out.