I just ordered Flex 6600 with Flex control + Mic & acc. and confused with all the manuals

Rej, The radio user guide provides information on the box. How to set it up, specs, ports, etc. so if this is a new radio for you you should read it to get familiar with the radio. The SmartSDR guide will give you more details on the software that runs in the computer. This will provide more o the operational information, such as using the slices, modes, profiles, adjustments, etc. I recommend reading this as well so you get to know the capabilities of at least have it handy when exploring the software. There are also quick start guides, which cover a bit of both documents and will get you on the air. You will find that mostly it is pretty intuitive, but the manuals have great operational tips. Eduardo, KC8R