A content calendar is a shareable resource that you can use plan your marketing activities. It'll help you to visualise how your content is distributed throughout the year.
This allows you to:
Plan content around key events or important dates
See where you have gaps in your content plan, with plenty of warning to line up more content
Make sure you have your content ready in plenty of time to publish
Identify your topics/audiences by creating your personas.
Collect your content assets and include:
Images of team activities or fundraising events can be used
Graphic assets - you might want to use a free tool like Canva
Stories from those who have been or are currently receiving help from your organisation
Artwork, poems, models created during sessions run by your organisation or by those who you are working with
Videos of your team sharing expertise or their stories as to why they are working for your organisation
Schedule, publish, promote, track and tweak any content. Have regular editorial planning meetings to plan the next publishing period, either monthly or quarterly.
Get more information about content calendar here.