Full use of the tools and information offered (including pdf files) is best carried out on a computer or tablet rather than a mobile phone.

If you decide to adopt the principle offered, you will be maintaining spreadsheets, which will take only a couple of minutes each day, once set up.

You will need access to spreadsheet software. Highly-acclaimed open-source (free and non-commercial) spreadsheet software is available. If you do not already have spreadsheet software visit: https://www.libreoffice.org to download the software. This is a direct link to the source: LibreOffice.org is a volunteer-driven project.