Hi, welcome
The Mac binaries apparently mistakenly link to shared hidapi instead of bundling it inside the binary. selsta (the person who builds mac binaries) should fix this soon. If you can't build yourself, you will have to wait for this first, or install hidapi on your system.
The most basic game mechanic is creating buildings. For this, you first need to have some gold. If you're familiar with Monero, you mine Townforge gold in the same way as monero. If you're not, then you can just click "start mining" in the game, in the "node" section of the UI. You should see your wallet balance increase from time to time. When you've got some gold, you can then deposit some of it into the game, by clicking "deposit" (or "create account" if it's the first time you're playing) in the player section of the UI.
Once you've got some gold in the game, you can then explore the land and select a plot of land to buy. Different locations are more or less suited to various things, but for now on testnet you can select anywhere that's not already owned by someone else. Select the rectangle encompassing the area you want to buy, and press ""buy land" in the commands section. This area must be sized between 8 and 256 squares on either side.
Once that's one, you can build a building on this land. There are a handful of building types available currently, the simplest one is "basic residential", basically simple housing. In the "flag" section of the UI (flag really means plot of land, historical reasons), click on "building settings". Select the building type you want. You'll see how much it will cost to build it in labour and materials. At this point, you don't have any labour nor materials in your inventory, so you can click on "Markets" near each requirement you're not meeting (all of them at start). This will open the P2P marketplace, pre-fill the amount you want to buy. You can click on buy. Once you've done that for all the materials you need, you can click OK, and your building will be built.
This building will earn gold 4 times a day provided you have enough wood (for heating) and food (for eating) for it in your inventory. So buy some wood and food in that same marketplace again, and you're set. Four times a day, your building will pay land tax and earn income from the town treasury. You should aim to have the income be more than the tax
You can then build a 3D structure to represent your building. This is optional, but makes more a much nicer world. This 3D structure will use up the budget you've already paid for when creating your building. Select a material with X and add/remove blocks with QEZC and a few other keys. You can set those keys to your preference in options/controls (press escape to go to options, or click in "options" in the commands section of the UI).
All of the above is on the chain, so any action needs to be mined. There's a block every 30 seconds on average, so your actions are a bit delayed, but you can do several things at a time. Mining involves verifying actions abide by the rules of the game, these are the rules that cannot be broken. For example, if you try to build a building without having the necessary materials in your inventory, other nodes will reject your attempt.
There are many other things you can do in Townforge, like researching the tech tree, building up prestige from collectible coins and gemstones, generating building materials for sale to others (or for your own usage), farming, etc. You can also learn how influence works, and how ground maps work, those both influence how your building performs.