This mod (which, as a reminder, has
https://github.com/minetest-mods/unifiedbricks as its main repo now) has mostly been converted over to use the new param2-based coloring scheme.
What this means in practice is that you can get a colorized brick block by simply placing a standard, default brick block on the ground, and then just right-click it while wielding some dye. If you dig the bricks, you get back default brick and the dye you last painted it with.
The same holds true for the clay blocks - place a default block of clay and right-click it with dye, or dig a colored clay block to get it and its dye back.
To get the "multicolor" bricks, place a brick block into the crafting grid, along with three portions of appropriate dye colors (see first post). These blocks cannot yet be further-colorized.
Please note that minetest_game brick stairs and slabs are not yet supported.
For the single-color bricks, the mod actually uses a mesh node to overlay the mortar texture onto the colorized, underlying bricks, so that the mortar remains grey. This may change in the future (and would require another engine update).
You will need a Minetest engine build made on January 24 (actually git commit d04d8aba), or newer, an equivalent update for minetest_game, and the latest git of Unified Dyes, otherwise newly-placed bricks can't be colored and you'll get unknown items for any existing colored bricks.