Install all dependencies:

sudo dnf install \
  git \
  ninja-build \
  meson \
  gtk4-devel \
  libadwaita-devel \
  json-glib-devel \
  libsoup3-devel \
  libarchive-devel \
  desktop-file-utils \
  libgee-devel

Clone the GitHub repo and change to repo directory:

git clone https://github.com/Vysp3r/ProtonPlus.git && \
  cd ProtonPlus

Build the source:

meson build --prefix=/usr && \
cd build && \
ninja

(Optional) Install application:

ninja install

Start application:

cd src && \
./com.vysp3r.ProtonPlus

Install the distro dependencies using your package manager (apt, dnf, pacman, etc):

sudo <insert your distro package manager and install options here> \
  git \
  flatpak \
  flatpak-builder

Add the flathub repo to your user if not added before:

flatpak --user --if-not-exists remote-add \
  flathub https://flathub.org/repo/flathub.flatpakrepo

Install the needed runtimes for flatpak:

flatpak --user install \
  runtime/org.gnome.Sdk/x86_64/43 \
  runtime/org.gnome.Platform/x86_64/43

Clone the GitHub repo and change to repo directory:

git clone https://github.com/Vysp3r/ProtonPlus.git && \
  cd ProtonPlus

Build the source inside the "build-dir" in the repo directory and install for the current user:

flatpak-builder --user --install --force-clean \
  build-dir \
  com.vysp3r.ProtonPlus.json

Start application:

flatpak --user run \
  com.vysp3r.ProtonPlus