Basic usage - metootem/TF2-Dedicated-Server-Manager GitHub Wiki
Here's a step by step guide for setting up the most basic TF2 server
1. Upon opening the app for the first time the first thing that will show is TF2 DSM Settings. In here you'll have to specify a directory where your server folders will be maintained.
1a. Click the + icon and select a directory where you want your servers to be in.
1b. After specifying a server directory go ahead and press Apply. You can close this window now and move onto the main one.
2. On the top left corner of the main window there's another + icon, which this time adds a new server tab. Click it and give the tab a nickname.
2a. If you have multiple server directories set up, you'll also be prompted to select in which you want to install this server to.
3. Write a name for this server's folder, which will contain server files.
4. Press Apply and the app will create the server folder inside the specified server directory.
5. You now have the ability to install the server itself. Press Install to start the process.
5a. You may be prompted to download SteamCMD, which is required to install the server. It's recommended to click Accept.
5b. A SteamCMD window will popup showing progress of the installation. Output may take a while to show (especially on Windows) so please be patient.
6. After SteamCMD successfully finishes downloading server files you can go back to the main window and press Start to open your server.
6a. You can connect to the server through the app by pressing the Connect button. You'll be prompted to join with either Public IP (requires port forwarding) or Local IP (only you and people in your network can use this one).
6b. When an update for TF2 is available, you'll have to update your server as well. You can do this by pressing the Update button.
6c. Hover over any object in this window to show a description explaining what they are for.
And that concludes this guide explaining the most basic use of this app.
You can go check out the configs guide to learn what the Configs tab (on the right side) has in offer.