Hey Investors and BiggerPockets!

I am struggling with the timeline of getting a loan for a flip, offering/negotiating, estimating costs, appraisal and developing your scope of work. This has a lot to do with I'm new into real estate from the medical field and iv also never bought a house even for personal use. Where I get snagged is, lets say I find a property on market on the MLS. Supply is low at the moment so being quick has advantage. Here comes the confusing issue to me:

1.) Since I will need to finance my first deal how do I know how much to ask for in financing to get pre-approved if I don't know how much the property will cost since I haven't found it yet?

2.) Lets say I find a property that fits my criteria. However...how will I be able to analyze the property and get a contractor to give me a estimated repair cost to know if it is actually a deal or not without making an offer beforehand? This also not letting me negotiate a more fair price if the property is not valued as much as they want and or needs a lot of repairs. 

It all feels backwards to me and I know I need to be quick in todays market. Id like to develop a scope of work and schedule work deadlines before closing on the house. I have searched forums without any luck. 

Probably a lot to unpack in those questions, Sorry. 

Thank you to anyone who has some better insight for me. Hope everyone's business is running smoothly! Cheers!