The teaching-to-fish problem is that
@loaded runs Apple gear and the VM seemed to be too much for the machine so the go-to (Win) quarter-wave modeling tools (
HornResp,
Akabak (16-bit), MJK (NLA),
AJHorn ($$$),
Leonard Audio, spicyTL) were/are out (as well as XSim) for the moment... I don't know how to help with that--hopefully someone Apple-wise has input?
Going by hand, start where
GM sez. 
Alternatively, if using say WinISD etc, one can use
xrk's method that
@PeteB linked to for a start. Either way, the whole point of MLTL's is to use the
standing waves for extension (at the cost of ringing) so the driver & port offsets should be finalized by checking in one of the above-listed modelers or similar to avoid a
squiggle. There really isn't a need to take hip-shots in 2025 anymore (ie use HR). Still, if you can't run HR, a person has to start somewhere, so use GM's ratios or, if you're tapering a very long one, you can start w/
Bob Brines' numbers.
If one of the "canned" form-factors of
Brian Steele's worksheets looks applicable, an iterative process in Excel and HR can save a lot of time in the "packaging exercise" vs. back and forth in CAD/drawing. (If not a Win user, note that those sheets need the macros so LibreOffice etc doesn't always work right with all of them and I can't recall which work and which don't at this instant.) If you want more 3-D (FreeCAD) packaging interaction with HR instead of Excel, check
LordSansui's site for a few foldings of tapered (end-terminated) pipes similar to what Brian has (but I've not used them and don't know if they include driver area like Brian's). (Some people mean a both-ends-closed + port when referring to MLTL's...DIY'er lexicon is fungible. For max clarity, refer to one- or both-ends-closed, straight, increasing, or decreasing taper and everyone will always understand what you mean vs. all the acronyms).
) 
