Do a little research on the science of launching rockets. Scott Manly's tutorials are the best way to learn the game, and his interstellar quest videos are a good way to see what the time comitment (it's a big one) can do. KW Rocketry is one of the best KSP mods powered by nose cones, fuel tanks, decouplers, fairings and a brand new engine system. I recommend Science mode once, all the way up the tech tree so you will know how useful parts are but don't have to optimze for financial returns (aka, cheaper rockets) 2. Career mode requires science to unlock parts and money to purchase them.
Career mode can overwhelm the game's new comers because they don't know how to play yet, and it's mainly there for veterans of the game like myself or some of the popular youtube channels. Science mode is the best to start with as you require research but not money to unlock parts. The s The job mode has gone out let’s focus on PC, Mac and Linux editions, and sees players managing their budget while performing research, crafting spaceships and hiring employees. 22 update that contributes career mode in to the mix, and much more. When the newest patch came out I had to create a new game three times just to finish all four of the first contracts before I ran out of funds. As far as what mode to start in, I would say science mode because sandbox is useful for testing out new ideas, but money, science experiments, and the tech tree are disabled and you are given a barrage of parts that you don't know how to use just yet. Kerbal Space Program developer Squad has released a brand new. Kerbal Space Program career mode now has contracts, and building space ships on career mode now cost the game's form of money.
Mods are great fun and really improve some aspects of the game, but from my experience, avoid them while your learning because they can easily over complicate things.
I kow how you feel, and I think I can help and shed some light on what the other commenters are saying.