Looking To Download YT Videos & Tracks From Soundcloud- What's The Best Method(s)?

The most basic of basic usage of it is just doing youtube-dl.exe <yourlinkhere>, that will pick the “best” quality for audio and video by default and put it in the same directory where the exe is located.
You can use youtube-dl.exe -F <yourlinkhere> to list all available formats (that are numbered), e.g.:

[tarulia@localhost]~% youtube-dl -F "https://www.youtube.com/watch?v=4lxxjz6-lmM"
[youtube] 4lxxjz6-lmM: Downloading webpage
[info] Available formats for 4lxxjz6-lmM:
format code  extension  resolution note
249          webm       audio only tiny   50k , webm_dash container, opus @ 50k (48000Hz), 1.91MiB
250          webm       audio only tiny   61k , webm_dash container, opus @ 61k (48000Hz), 2.31MiB
251          webm       audio only tiny  115k , webm_dash container, opus @115k (48000Hz), 4.36MiB
140          m4a        audio only tiny  129k , m4a_dash container, mp4a.40.2@129k (44100Hz), 4.88MiB
160          mp4        256x144    144p   69k , mp4_dash container, avc1.4d400c@  69k, 30fps, video only, 2.62MiB
278          webm       256x144    144p   71k , webm_dash container, vp9@  71k, 30fps, video only, 2.69MiB
242          webm       426x240    240p  110k , webm_dash container, vp9@ 110k, 30fps, video only, 4.18MiB
133          mp4        426x240    240p  155k , mp4_dash container, avc1.4d4015@ 155k, 30fps, video only, 5.85MiB
243          webm       640x360    360p  192k , webm_dash container, vp9@ 192k, 30fps, video only, 7.25MiB
134          mp4        640x360    360p  290k , mp4_dash container, avc1.4d401e@ 290k, 30fps, video only, 10.92MiB
244          webm       854x480    480p  308k , webm_dash container, vp9@ 308k, 30fps, video only, 11.61MiB
135          mp4        854x480    480p  513k , mp4_dash container, avc1.4d401f@ 513k, 30fps, video only, 19.34MiB
247          webm       1280x720   720p  590k , webm_dash container, vp9@ 590k, 30fps, video only, 22.24MiB
302          webm       1280x720   720p60  846k , webm_dash container, vp9@ 846k, 60fps, video only, 31.86MiB
136          mp4        1280x720   720p  994k , mp4_dash container, avc1.64001f@ 994k, 30fps, video only, 37.44MiB
298          mp4        1280x720   720p60 1381k , mp4_dash container, avc1.640020@1381k, 60fps, video only, 52.01MiB
303          webm       1920x1080  1080p60 1306k , webm_dash container, vp9@1306k, 60fps, video only, 49.19MiB
299          mp4        1920x1080  1080p60 2653k , mp4_dash container, avc1.64002a@2653k, 60fps, video only, 99.91MiB
308          webm       2560x1440  1440p60 4855k , webm_dash container, vp9@4855k, 60fps, video only, 182.84MiB
315          webm       3840x2160  2160p60 10896k , webm_dash container, vp9@10896k, 60fps, video only, 410.31MiB
18           mp4        640x360    360p  374k , avc1.42001E, 30fps, mp4a.40.2 (44100Hz), 14.11MiB
22           mp4        1280x720   720p 1122k , avc1.64001F, 30fps, mp4a.40.2 (44100Hz) (best)

(note I’m on Linux, so no .exe there)

To pick a format from that list you need to use the number in the first column. To get an MP4 audio you would use:

[tarulia@localhost]~% youtube-dl "https://www.youtube.com/watch?v=4lxxjz6-lmM" -f 140
[youtube] 4lxxjz6-lmM: Downloading webpage
[download] Destination: L1 Giveaway! TerraMaster TD2 - Thunderbolt w_RAID-4lxxjz6-lmM.m4a
[download] 100% of 4.88MiB in 00:00
[ffmpeg] Correcting container in "L1 Giveaway! TerraMaster TD2 - Thunderbolt w_RAID-4lxxjz6-lmM.m4a"

Obviously there is a lot more you can use for more flexibility, but that is the basic usage.