guidance

When looking at horary charts with affairs. Do you turn the chart and start in 5th or 7th. I've read both but I'm going to turn and go with 5th. Then what happens next? Do you follow his ruler or move forward to L5 or L7 , L4?
Please do not give all answers want to try to work it out step by step.I will respond back to get guidance.

So - to begin looking at the 5th house with Venus (7th house Ruler) sitting in the 5th, I would say there is a another party of interest. I am going to say
I am Saturn First house ASC
He is Mercury L(1)
Female involved is L(5) Venus
Aspects Venus sextile Saturn. Is this someone I know?
Mercury is semi square Venus at 0 degrees. Is this indicative of a meeting?
Moon is square Mercury in 3 degrees

Clearly state your question. What determines the ruler of the ascendant is who is asking the question. if you are then looking at someone related to the quesited, you turn the chart from their house as their first.