First thing: Try starting with the dharmakṣetre example (opens in new tab). This sets Gītā 1.1 as the input in IAST Romanization and transliterates it to Devanāgarī.
For different transliteration output, use the "Output scheme" dropdown and click "Transliterate" again. To learn about supported transliteration schemes, visit the skrutable manual on Github. You can also use the "Swap" buttons to move things around as needed.
Now click between the "Transliterate", "Scan", and "Identify Meter" buttons to calculate and display skrutable's three basic outputs.
Scansion is line-by-line, and it doesn't matter how many lines or how much content you enter. This mode is especially good for fiddling and exploring.
Meter identification, by contrast, effectively requires four lines of content, corresponding to four verse quarters or pādas. You should use this mode when you believe you're dealing with a whole verse (half an anuṣṭubh śloka works, too).
You can use the "Re-Split Pādas" dropbox to decide whether to use your own line breaks or to let skrutable try and find them for you. The option "resplit_max" uses the most brute force and requires the least thought, while "resplit_lite" better respects whatever line breaks (or ';' or ' / ') you provide. Or, choose "none" in order to evaluate exactly the (necessarily four!) lines you input.
Definitely also try changing the mix-and-match scansion detail options with the checkboxes below "Scan". These also work for the whole-file mode described below.
To learn more about working with Sanskrit meter, the skrutable manual on GitHub provides some very basic pointers.
And to automatically split the compounds "dharmakṣetre" and "kurukṣetre" and the sandhi-coalescence "caiva", just click "Split Sandhi & Cpds". This function is relatively slow for single examples, and its results are not always 100% correct (see the Hellwig-Nehrdich paper for details), but it's quite useful nonetheless. This is the first time it's been easily available online, and you can enter material of any length, even with punctuation. The output is also transliterated.
If you're feeling more ambitious, you can also do transliteration, meter identification, and sandhi/compound splitting on whole files.
For transliteration, just set your input and output schemes as normal, but then instead of hitting the "Transliterate" button, hit the "whole file" button underneath. Continue through the next screen to upload your file, then look for the output in your usual download location.
Whole-file sandhi/compound splitting is exactly as easy. Note also that it is relatively fast, and not at all as slow as single-example processing would lead you to expect.
Doing whole-file metrical analysis is also similar, but the input must be more carefully prepared, with one verse per line and no extraneous material. See the "Scan GRETIL" page to get a better idea of what this entails.
If you want to try out the whole-file meter identification function right away, you can use these prepared input files: