Q.Please Advise This Is For Mandevillas, The Instruction Was Use (5ml) Epsom Salts Dissolved In Water,however,it Does Not Mention Wi
th how much water. Please advise

Certified GKH Gardening Expert
That will get you about 1/4 of a gallon in my experience! You can use between 1-2 tablespoons per gallon, depending on the results of your soil test.
https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/epsom-salt-gardening.htm
https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/testing-moisture-in-plants.htm
https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/testing-soil.htm
https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/soil-ph-plants.htm
https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/test-soil-for-pests-and-diseases.htm
https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/making-sure-soil-drains-well.htm