This is a solid tool for helping you create pre-industrial fortifications in a fantasy setting. You could use these tables for non-fantasy settings if you're willing to skip over the fantasy elements when they arise. There's a Visual Style table that names various historical and fantasy styles (without describing them), but several of the tables use medieval European castle terminology in particular.

The document helps you spec out the fortification, but it's not a map generator and there are no maps or diagrams included. You wind up with a list of elements and descriptions, but if you want to map it out, roughly or on a map grid, that's all on you.

If you're creating a fortification from scratch, you could use most or all of the tables to generate the fortification randomly, using your judgment along the way to decide what's worth rolling up and how it all fits together. You'd use most tables once each, and some tables more than once. Rolling it all up from scratch and forming your mental image of the place could take a little while, so you wouldn't do that in the middle of a session. If you have an existing fortification or decisions you've already made, you can roll on only the tables you want. They're modular that way. You could use some of them for ad hoc rolls during play to answer specific questions, such as the current status of the place.

There are a couple of tables that refer generally to the area around the fortification (purpose and general location), but there's nothing about generating the fortification's support systems, such as surrounding villages, fields, and other resources. If you want to model the fortification's economy, you'll need other tools. There's also no distinction between the features that would appear in a fortification that's embedded in a city, for example, versus a lone wilderness outpost.

The document is system-neutral, so there are no prices, statistics, or modifiers. Converting this to your RPG's stats is on you. Similarly, there are no exact size or population numbers. You get abstract size and population units that give you an idea of relative size or population, but turning them into specifics is left to you (if you want the specifics).

Many of the tables include descriptions of the entries. If you don't know what machicolation is, for example, there's a brief paragraph that explains it.

The document provides a method for determining how many military and civilian "population units" (PU) are present. The PU is a relative term, not an exact population count. If you have 3 military PU and 2 civilian PU, it's up to you to decide what those might mean in terms of numbers or subgroup roles.