I am in charge of the network for a small non-profit school. I am not an IT professional, but rather a tech-savvy person with a willingness and desire to learn. We recently deployed a very simple Wi-Fi network on our campus consisting of 3 Ubiquiti UAP waps, and an RB2011L-IN router. We are connected to the WAN through a residential DSL modem/switch that gives us a lightning fast 5MB/s down on a good day. 
The system needs to support about 75 clients including students and staff.
The problems we are having is just general slowdown when connected through the LAN here, even with super light (10 clients) load. Iām looking for some general info on how I can troubleshoot this and where the choke point could be. I did ping which gave me back 17.6% packets loss vs. 4.2% when connected directly to the DSL modem.
The RB2011 is pretty much configured stock. That is, eth1 setup for wan, eth2-4 are unused. Ports 7-10 are slaved to eth6, and I have the Ubiquiti APs connected to 6,7,8 respectively. Any help anybody could give me would be greatly appreciated. Admittedly, I may have bitten off more than I can chew with RouterOS, but for our needs and budget it seemed like a good purchase.
Thanks. 