I learned in Thailand about the Dhamma. It was kept very simple.

Regarding karma: if you plant a mango seed, you get a mango tree. It’s impossible to plant a mango seed and get a potato.
Whatever we plant we have to reap the results at some point. Whether that’s in this existence or another depends on many things.
It takes a lot of understanding though when you have done only mainly good in this life and see only bad come back. That is very testing of your wisdom. But then look at the teaching of the Buddha where He said that if we bones from our every lifetime were piled up they would be higher than the hugest mountain (sorry if not an exact quote!!!) – the tears we have shed would be more vast than all the oceans… then start to reflect on how much we have ‘planted’.

We were taught to reflect on this, understand it and turn things around to see that all we see before us is a reflection of all we have done in the past. Our hope is only not to create any more bad karma and seek forgiveness for that which we have done and cannot remember throughout countless existences…