- )
Read guides for game advancement and resource farm location (for example, this one https://docs.google.com/document/d/1vR41ia5_FmKfyfL9oGakbTc1qkzDJuL3AQ7-F40gmW4/edit#heading=h.9af2e9196kyx). For platinium you have to buy them with real money or participate to in-game trades (see warframe market to make an idea about what you can sell for plat).
Don't forget that warframe is really rich of content so take time to learn and proceed at your own pace. Just asking for free plat and resources won't benefit you.
Good continuation.