Download source from one of [2] e.g.:
https://mirror.dogado.de/sage/src/index.html
Unzip sage-10.2.tar.gz to home directory $HOME. Optional rename directory to sage.
Change into the installation directory:
cd sage
Prepare configuration:
./configure
Build from source:
make
Install jupyterlab
./sage -i jupyterlab
Run sagemath
./sage -n jupyterlab
See also:
[1] doc.sagemath.org/html/en/installation/source.html
[2] www.sagemath.org/download-source.html
[3] doc.sagemath.org/html/en/index.html
Reference:
[4] SageMath, the Sage Mathematics Software System (Version 10.1), The Sage Developers, 2019, www.sagemath.org