First time charting

Now my fiancé and I have been trying since January. Been taking prenatal, started estrogen supplements this month and started tracking my bbt temps. Now my cycles have always been out of wack from 38-50 days. Found I have low estrogen and was suggested to try tracking bbt.

Here is my chart. You can see we are trying to conceive. Got positive ovulation test yesterday and this morning. Have had multiple session with my parent and even tried pre-seed last night. Hope my chances are high.

My question is I hear you can tell if your pregnant by bbt charting. How would I be able to tell so I can keep watching.