1)Choose 2 minimum values, add them and put in parent node of both.

2) Place smaller values at left.

first the set is given above, we choose 2 smallest values ie 1 and 3 , add them and put in parent. So parent 4, left N and right S.

Put this 4 again in the set and now again choose 2 minimum from set which result in minimum sum at next parent. Now these are 4 and 4. You can arrange in any order in similar weight case.

Next case will be 8 and 10 so you have to put 8 at left and 10 at right.

Your 1st tree is correct except 10 will be at right to 8.

A =10, E=15 , I=12 , S=3 , T=4, P=13, N=1

The Huffman coding says that

1)Choose 2 minimum values, add them and put in parent node of both.

2) Place smaller values at left.

first the set is given above, we choose 2 smallest values ie 1 and 3 , add them and put in parent. So parent 4, left N and right S.

Put this 4 again in the set and now again choose 2 minimum from set which result in minimum sum at next parent. Now these are 4 and 4. You can arrange in any order in similar weight case.

Next case will be 8 and 10 so you have to put 8 at left and 10 at right.

Your 1st tree is correct except 10 will be at right to 8.