This is the content of a sample Tecplot data file. Data is one dimension i.e. U vs. X for 20 points. I was using a C program to solve my equations and at the end of my program, I had a small subroutine which writes this information into a .PLT or .DAT file which is then used in Tecplot. I think this should suffice for very basic data plotting. If there is anything specific, I would like you to post that in your question specifically.
VARIABLES="X","U"
ZONE F=POINT
I=20
0.00000000 0.00000000
5.00000000 0.28632834
10.00000000 0.52683960
15.00000000 0.68127329
20.00000000 0.72938137
25.00000000 0.67444474
30.00000000 0.54886950
35.00000000 0.40325212
40.00000000 0.28895415
45.00000000 0.24889311
50.00000000 0.30863131
55.00000000 0.46400776
60.00000000 0.67566198
65.00000000 0.93921596
70.00000000 1.29542423
75.00000000 1.51374208
80.00000000 1.35904516
85.00000000 1.01646862
90.00000000 0.54498717
95.00000000 0.00000000