Hello!
We have MikroTik hEX RB750Gr which is connected to this ISP and after it cisco sg 300-20 switch. Now we have bought Mikrotik hap ac in another room. It is connected to the same switch. PC is connected by cable to that router. We have internet on it but no local network. Can somebody help me with that? What should I do to get local network working?
First, you have to draw what you have in mind, as it is absolutely unclear to me what local network you have in mind and whether the Cisco switch is at the LAN side of the hEX or on its WAN side. The drawing should show the L2 and L3 topology of the network and as you mention hAP, also the relationship of the wireless network to the wired segments. And the export of configiration of both Mikrotiks, following the anoynmization hints in my automatic signature. A photo of a drawing by hand will do, no need to spend hours drawing it using a mouse.
is this a home network or a business setup??
Concur, draw/provide a diagram.
Then post both configs…
/export hide-sensitive file=yourconfigmay23
Sorry! I’ve got no notification on this topic. Here is the scheme. But we have worked out it and now all is fine. Sorry for bothering 
