The good news is you must know that engineers must learn to read and write specifications before they can learn how to design.
So don't even try. You must start with good specs !!! (lots of measurable values)
What does it do? [ppm, ppm/'C, Rs, parallel, series or harmonic (overtone) etc ? tolerance?/stability?/aging? sine or square out?
Once you know what is required, your options are "make or buy" on every little circuit. Discrete, IC, module or the final product? What makes radios bad or better?
Fortunately, XO's are cheap now so you don't have to learn a book's worth of info. Just buy a ready-made Crystal Oscillator for not much more than the crystal. But what specs?
X = Crystal or Xtal (x looks like a criss-cross)
XO = Crystal Oscillator
VCXO = Voltage Controlled XO
TCXO = Temp. Compensated XO ( often -40 ~ +70'C or 0 to 70'C) graded by tolerance in ppm, parts per million (error) at room, 25'C and stability = over Vcc & temp. range.
VCTCXO Volt. controlled TCXO (THese can be nulled)
OCXO ( Ovenized SC cut crystal ~1000x more stable and 200x more expensive for 1e-11 type accuracy. The others above are all AT cut X's. Of course, DIY AT-cut OCXO's are cheap if you know-how but that takes a 2 stage thermal design and a 2 stage heater at the 3rd order minimum.
DTXO Digitally tuned XO with PLL and you serially program the string into its non-volatile memory, so one xtal can do many frequencies.
I've probably left some acronyms out, but you'll figure it out.
Digikey has all of these.
What is a crystal
What are the common attributes must be understood?
Q for an X is ~>10k whereas,
Q for an LC resonator based on impedance ratio with R might be 100 to be reasonably stable.
I can remember being an undergrad and reading the ARRL Handbook with glazed eyes as if, I was reading a book on vector economics and then 30 years later asking a grad student from Philly when I was in San Diego, "what is a crystal ?" and he admitted no idea. Yet upon graduation in EE, I had the necessary theory and self-taught skills to understand how to read datasheets and schematics and designed several 2 stage Xtal VLF filters for a Doppler Rx easily in my 1st job.
What are the Filter Specs?
Again same thing , don't think about design until you find your specs.
What is the best filter spec and is it possible to learn how in a short time? For each stage, RF, IF , Antenna, PS, how many stages, what group delay, BW, Q stop band?
How to understand Filters the easy way.
Instant design with all the variables on sliders. Choose circuits> larger passive filters > choose order 7th > increase spectrum , > choose centre frequency, BW Chebychev, Ripple dB, add phase response, Pole Zero plots and change to any spec, eg. 2.4GHz BW 30MHz 5th order or 12 th order .. (random)