How to Backup Save Files
Salt takes advantage of Steam's cloud saving in order to keep your save files as safe as possible and synchronized between all of your computers. If you want to manually backup you saves, the instructions are below.
Your Salt saved data is stored locally on your computer within the sub-directories of Steam's installation directory, at [SteamInstallationDirectory]\userdata\[YourID]\327860. More specific instructions on how to find the correct directory, including how to determine your ID can be found in the steps below.
1. Find your Steam installation directory. If you don't know where this is, find the shortcut that you use to open Steam, and right-click it and select Open File Location. If this takes you to another shortcut, you can right click that new shortcut and select Open File Location again.
2. In your Steam installation directory, open up the folder called "userdata". Within this folder will be one or more folders with the title of a large number. This number corresponds to an ID for your steam account. If there are more than one folders with numbers, you will need to determine which one corresponds with your Steam account. One way to determine this is to open up Steam, hover over your name at the top center, and select inventory from the dropdown. Then click the Trade Offers button near the top right of the page. In this page, click the "Who can send me trade offers?". In the Thrid-Party Sites section of this page is a trade URL. Part of that URL will be ?partner=NUMBER, where NUMBER is a series of numbers. That number corresponds to the name of the folder in the userdata folder. An example URL is https://steamcommunity.com/tradeoffer/new/?partner=439449740&token=rJKFtDAW.
3. Look for the folder titled 327860. This folder contains your Salt save data. Copy this entire folder and save it elsewhere. You now have a backup of your Salt save data.
Restoring the Backed-Up Save File
If you want to restore a backed up save, you must first start Salt. Once Salt is started (just in the main menu is fine) then replace the 327860 folder with the version of it that you backed up in step 3. After this, quit Salt. Note that it is important to have Salt running during this step or else Steam will replace the folder back with your current save stored in its cloud.