Apilan and kota mara are two terms that come from the Filipino language. Apilan is a Tagalog word which means "stack" while kota mara is a Visayan term that refers to a small makeshift house or hut.
Imagine you have a bunch of blocks to play with. If you stack them one on top of the other, you are making an apilan. It's like making a tall tower with your blocks. The higher you stack them, the taller your apilan becomes.
On the other hand, a kota mara is a little house made of materials that are not so sturdy or permanent, like wood scraps or leaves. Some people make kota maras to live in for a little while, like if they go camping. A kota mara is kind of like a playhouse that you might build in your backyard, but it can be used for sleeping or cooking or other things like that.
So, in summary, apilan means to stack things up high like building a tower with blocks, while kota mara means to make a small, simple house out of easily available materials like wood and leaves.