From the author's README on Thunderstore

Andy Anderson Shape 290 — Heron Deck

A custom deck shape modeled after Andy Anderson's 9.13" Shape 290 deck, including his pro model Heron graphic.

Works with all standard deck graphics; the included Heron graphic is optional.

Compatibility / Load Order

Load this mod before other deck shape mods to see the Shape 290 deck.

Model replacements affect every board that uses the replaced asset. When multiple mods replace the same asset, whichever loads first takes priority. If another deck shape mod loads first, its shape will appear instead.

Install Andy Anderson Shape 290

You need ReSkate and your own copy of skate. on Steam.

Open ReSkateLauncher.exe and go to MODS.
Search for Andy Anderson Shape 290 and click install. The launcher also installs anything it depends on.
Press PLAY. In game, the MODS tab of the ReSkate menu (Insert) turns it on and off.

Or install it by hand: download the .zip and drop it on the launcher window, or unzip it into its own folder in Mods\ beside Skate.exe.

Maps show up in the ReSkate menu's level list. To join a server running a custom map, you need the same map installed. If the game won't load after installing, see known issues.

skatemods doesn't host or review this mod. The download comes straight from Thunderstore. Only install mods you trust, because scripts can run code.