Is there any way to level up the troops I have bunch of one stars that could be merged to make a stronger one
yes, after you get your Stronghold to level 10, you can convert one of your buildings (preferably the one you use to craft things) to Barracks, and there, you can level your troops up.
Thanks for letting me know it was frustrating sitting on them
Warning - it take a TON of food to level up troops. Only do a few at a time and watch your food count. It takes 250k iron to build your barracks but only 10 seconds to convert it. No long building or research time
The building you want to convert to a barracks also has to be at level 5, at least.
Convert a level 5 forge into a barracks
yeah, those above are all fair warnings. I wasted all my food having fun with my 3-star troops