The IPA (International Phonetic Alphabet) is a collection of characters that can be used to transcribe any human voice sound, from any language, in a way that all linguists and language enthusiasts worldwide can understand, regardless of their mother language or cultural background. Because the IPA includes symbolic representations of English and non-English speech sounds, trying to decipher its extensive body of characters can be a challenge for someone who just wants to transcribe an English word. To transcribe an American English word successfully and with limited confusion, your best bet is to find and use an IPA symbol chart that only includes speech sounds from American English.
Briefly study an American English IPA chart, and become comfortable with its symbols and their associated pronunciations. People new to the IPA are sometimes confused at first, because certain symbols don't always make the sounds you'd expect based on what you've learned about the English alphabet in the past. Certain sounds in English that we consider two-letter sounds (such as the "sh" sound in "shell," for example) are represented by just one character in the IPA. Take the time to learn and get comfortable with the different sounds and their symbols.
Use antimoon.com's IPA chart for this exercise, linked in the Resources section.
Slowly pronounce the word that you want to transcribe out loud to yourself. Ask yourself what sounds you hear. Try to write the word out using IPA notation, without referring to your IPA chart.
Look back to your IPA chart and pronounce the word again. Double-check any symbols that you're not sure about against the chart, and correct any mistakes.