So, there are excellent instructions in the manual for the 25" Schacht Tapestry Loom...but for whatever reason, when the loom is on my loom stand, the instructions are backwards because I cannot flip the loom so the heddle bar support is pointing down. Now, I know everyone can simply reverse the instructions like I did, but sometimes it is just easier when someone tells you how to do it. For example, when I am warping my loom while simultaneously helping my kids build legos, read books and not eat bugs, I like to not have to reverse things in my head. There are only so many tasks you can multi on before things go wrong.
Like I mentioned previously, the instruction manual has instructions for when the loom is horizontal and the heddle bar supports are pointing down toward the ground. My instruction are the exact same as these instructions except they are for when the heddle bar supports are pointing upward. This can be accomplished on a loom stand or by simply placing books or blocks under the frame of your loom.
Step 1: Using your loom stand, adjust the level of your loom so that it lays horizontal, heddle bar supports pointing straight up. You should begin standing with the loom oriented so that the bottom bar is closest to your body. Make sure you have the tension bar all the way down (so that you have the most room to tension your warp later).
Step 2: Put your warp bar in place against the rubber wedge. Make sure your warp thread is on a skinny cone or a compact ball so it can fit through all the spaces of the warping process without knocking the warp bar out of place. Tie your warp thread to the warp bar. (The warp bar and rubber stopper are located between the bottom bar and the central bar.)
Step 3: Bring the warp thread toward you, going under the bottom bar. Bring the thread over the topside of the loom toward the tension bar.
Step 4: Take the warp thread over the tension bar, down and under the loom, heading back toward the center bar. Take the warp thread under the center bar and turn the thread on the warp bar, passing once again under the center bar on the way to the tension bar.
Step 5: Once you get back up to your tension bar, you will still be under the loom. Pass the thread over the top of your tension bar and head back toward the bottom bar. You will be on the topside of your loom. Take it all the way to the bottom bar.
Step 6: Pass the thread over the bottom bar and going under your loom, take the thread to the warp bar. Pass the warp thread around your warp bar and head back to the bottom bar, passing the thread from the bottom side to the topside of the bottom bar.
Step 7: You have now completed the whole pattern of warping. You should repeat steps 3-6 until you have the desired number of warp threads on the top side of your loom. To me, the process of warping this tapestry loom is like make a series of M's and W's. Also, you should be able to run your hand (or a piece of paper) under your threads from the top of the loom down to the bottom, passing in front of your warp bar. If you cannot, that means you have crossed a thread and sadly it will need fixing before you can proceed.
One trick to keep yourself on track if you are having a little trouble crossing your threads is to wrap your loom with paper (like packaging paper or wrapping paper). Remove the warp bar prior to wrapping your loom with paper. Then, take your paper around your loom from the tension bar around the bottom bar and back up. Tape the paper together. This will require about 65" of paper length (which matches your warp length). Now you will have to place your warp bar back on your loom- the tricky part being that it now needs to be on the backside of your paper. However, this paper wrap will ensure you are going over or under when needed and will not allow for any crossed threads. Simply remove the paper when your warp is complete by sliding out from under your threads.
I hope this helps a little if your loom is turned around like mine. Really, it just gives an alternative way to warp- it is exactly the same as the recommended method, just with your heddles pointing up.