It's easy to connect to Servers – To find Partner Servers, just look for the “Servers” tab from the Minecraft game menu on your Windows computer, mobile device.
Start Port: This box is the port that the scanning will start on. Port in general range from 0-65535, but most Minecraft servers will on port 20000-30000.
For Bedrock Edition servers, make sure to enable "Allow Cheats" on the options page. If it's disabled, you have to enable it and restart your server afterward.
You can't grant access to only the /teleport command, but you can prepare a /trigger for them to use. First create three scoreboards for the coordinates.